+---------------+------+-------+-----------------+------+----------+-----+ | Reaction |S.G. | Solids| Urea |SO₃ |P₂O₅ | Cl | +---------------+------+-------+-----------------+------+----------+-----+ |[1]Faintly acid|1·020 | 44·20 | 23·8 | 1·38 | 2·39 | 4·08| | | | | | | | | |[2]Alkaline |1·034 | 127·9 |Nil (all reduced)| 8·30 | 13·41 |38·00| +---------------+------+-------+-----------------+------+----------+-----+ FOOTNOTES: [1] (1) Fresh urine. [2] (2) Urine after filtration through sawdust. '_Physical Characters._—(1) Pale yellow, clear, with a slight opaque zone from mucus, normal urine odour. '(2) Dark mahogany-brown colour—markedly opaque and somewhat turbid. A peculiar woody (resinous) odour, faintly ammoniacal. 'The "two ammonias" cannot be estimated by Wanklyn's process in the fresh urine, where there is so much urea, but in the filtrate they amount to— 0·032 Free and saline } per 1,000 0·0016 Organic } I have kept two test-tubes half filled with (1) and (2), tightly corked, in the warm cupboard of the laboratory for the past three weeks; the sample of fresh urine has become offensive, but that of the filtered urine is perfectly sweet, and rather pleasant to smell.' The filtrates from sawdust were a very dark brown colour, like 'stout' or 'porter,' and these have been evaporated to dryness without offence, and have shown no tendency to putrefy. Experiments conducted in the same way with peat have yielded a filtrate almost identical in appearance to the sawdust filtrate, inoffensive on evaporation and not putrescible. The filtrates from peat and sawdust were always of _higher specific gravity_ than the urine added. In order to ascertain how much urine could be got rid of by evaporation, I tried the experiment of using a flannel bag filled with sawdust or peat, and I found that with regard to one of these experiments (the bag being hung under a shed in the open between June 15 and July 20, 1895), only 81 ounces of filtrate having the qualities above given were obtained from 729 ounces of urine added to the filter. In this case 648 ounces of urine (over 40 lbs. weight) disappeared. In another experiment carried on in my room at University College I added (between May 9 and July 26) 626 ounces of urine, and obtained only 54 ounces of filtrate, so that in this case 572 ounces (nearly 36 lbs. weight) of urine had disappeared.